54 METEOROLOGICAL 



gradually augmented in magnitude until it as- 

 sumed the form and appearance of a phosphoric 

 zone subtending at his eye an angle of about 60 

 degrees, measured horizontally, and having the 

 apparent height of a few feet ; above this was a 

 dark band, and then again another zone of light. 

 These luminous zones of cloud were nearer the 

 earth than the storm clouds, and their brilliancy 

 lasted about a quarter of an hour. 



Beccaria assures us that the clouds over his 

 observatory at Turin frequently shed in all direc- 

 tions a strong reddish light, which was sometimes 

 so intense as to enable him to read ordinary print. 

 This nocturnal luminosity was especially observed 

 in winter, between successive falls of snow. 



When General Sabine and his crew were lying 

 at anchor at Loch Scavig, in the Isle of Skye, he 

 observed a cloud which constantly enveloped the 

 summit of one of the naked and lofty mountains 

 which surround that island. This cloud which 

 had been formed by the vapour precipitated near 

 the mountains after having been brought by the 

 constant west winds from the Atlantic, was self- 

 luminous at night, not occasionally, but perma- 

 nently. He saw frequently issue from it jets of 

 light, and convinced himself that this phenomenon 

 had nothing whatever to do with the Aurora 

 Borealis. 



We may add to these an observation of Nichol- 



